Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

3,766.

In titration involving sodium hydroxide and dilute hydrochloric acid, where would you place the base?

A.

in the beaker

B.

in the conical flask

C.

in a burette

D.

in the standard flask

E.

in the measuring cylinder

Correct answer is B

Add a few drops of indicator and put the conical flask on a white tile. Fill the burette with acid and note the starting volume. Slowly add the acid from the burette to the alkali in the conical flask, swirling to mix.

3,767.

By means of filtration, one component can be obtained pure from an aqueous mixture of sodium chloride and?

A.

potassium nitrate

B.

sand

C.

lead nitrate

D.

sugar (glucose)

E.

starch

Correct answer is B

Use enough water to completely submerge the sand-salt mixture. Stir or shake the mixture for a few minutes so that the salt dissolves in the water.

The sand is insoluble, so it will remain visible.

3,768.

Which of the following changes is physical?

A.

Adding iron filing to aerated water

B.

Adding sodium metal to water

C.

Cooling a solution of Iron (II) sulphate to obtain the hydrated salt

D.

Cooling water to obtain ice

E.

Burning the domestic gas (Utilgas) for cooking

Correct answer is D

No explanation has been provided for this answer.

3,769.

If hydrogen sulphide gas is passed into a solution of a pure iron chloride, a yellow deposit appears. If the deposit is filtered, a pale green solution is left behind. The pale green solution is

A.

dilute sulphuric acid

B.

dilute hydrochloric acid

C.

unreacted hydrogen sulphide in water

D.

iron (III) chloride

E.

Iron (II) chloride

Correct answer is E

No explanation has been provided for this answer.

3,770.

Consider the following equation H2O + 2Fe2+ + Cl2 ↔ 2Fe3+ + 2Cl- + H2O. Which behaves as an oxidizing agent?

A.

Fe2+

B.

Cl2

C.

Fe3+

D.

Cl-

E.

H2O

Correct answer is B

- An oxidizing agent is a substance that causes oxidation by accepting electrons; therefore, it gets reduced. A reducing agent is a substance that causes reduction by losing electrons; therefore it gets oxidized.

- Common examples of oxidizing agents include halogens (such as chlorine and fluorine)